[ANN] Darcs 2.16.4 release

On behalf of the Darcs team, I would like to announce the release of
Darcs 2.16.4 [1].

Quoting from the release notes [2]:

This release is mostly to fix http://bugs.darcs.net/issue2674 which can
lead to repository corruption. This is not quite as bad as it sounds,
since the broken changes that you could have recorded were consistently
ignored when applying the patch. This bug has been in darcs for a very
long time and even our own repos contain (ancient) patches with broken
move changes, and so far it hasn't caused us any trouble.

That said, there are certain patch commutations that will erroneously
(and unexpectedly) fail when such a patch is involved. We therefore
recommend to upgrade. You may also (after upgrading) run 'darcs check'
on your repositories to see if you are affected, and 'darcs repair' them
if that is the case. Fortunately, the broken move changes can be safely
eliminated from existing patches, and the improved repair command now
does exactly that.

Thanks to Henning Thielemann for bringing this bug to our attention.

[1] https://hackage.haskell.org/package/darcs-2.16.3
[2] https://hackage.haskell.org/package/darcs-2.16.3/changelog

Cheers
Ben
-- 
I would rather have questions that cannot be answered, than answers that
cannot be questioned.  -- Richard Feynman